Electrical Machines
On which of the following factor/factors the speed of a DC motor depends upon?

 Field flux.
 Armature current.
 Applied voltage.
 All of these.

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Electrical Machines
In DC machines, the interpoles are provided

 to counteract the reactance voltage and the cross-magnetizi
 to counteract demagnetizing effect of armature mmf in commutating zone.
  both (B) and (C).
  to make commutation spark less.

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Electrical Machines
If the applied voltage of a certain transformer is increased by 50% and the frequency is reduced by 50%, the maximum flux density will (assuming that the magnetic circuit remains unsaturated)

 changes to three times the original value
 changes to 0.5 times the original value
 remain the same as the original
 changes to 1.5 times the original value

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